Railway traffic controlling apparatus



June 23, 1 931.

G. W. BAUGHMAN RAILWAY TRAFFIC CONTROLLING APPARATUS Fil ed June 18, 1930 INVENTQR Q. W. Bauqhman, Q- afi/LZ,

2 ATTORNEY Patented June 23, 1931 UNITED STATES i amen- PATENT, OFFICE A GEORGE W. BAUGHMAN, OF PITTSBURGH, PENNSYLVANIA, ASSIGNOR TO THE UNION SWITCH & SIGNAL COMPANY, OF SWISSVALE, PENNSYLVANIA, A CORPORATION OF PENNSYLVANIA RAILWAY TRAFFIC CONTROLLING APPARATUS Application filed June 18,

My invention relates to railway trafiic controlling apparatus, and particularly to automatic train control apparatus of the code type One feature of my invention is the promsion, in systems of this character, of novel and improved means for insuring the pickup of a track relay on coded current after the removal of a shunt across the track rails.

I will describe oneform of apparatus embodying my invention, and Wlll then pomt out the novel features thereof in the claim.

The accompanying drawing is a diagrammatic view showing one form of apparatus embodying my invention.

Referring to the drawing, the reference characters 1 and 1 designate the track rails of a stretch of railway track along which trafiic normally moves in the direction indicated by the arrow. These rails are divided by insulated joints 2 to form a series of track sections, of which only one complete section AB is shown in the drawing.

Section AB is provided with the usual track circuit comprising a transformer T, the secondary 8 of which is connected across the rails at the exit end of the section, and a track relay Rconnected across the rails at the entrance end of the section. The primary 4 of transformer T is normally connected with the terminals X and Y of a source of alternating current through the back point of contact 6 of a code relay D.

The current supplied to the track rails is at times periodically interrupted by a codmg device C, comprising an electric motor 9 dr1ving a cam 10, which cooperates with a follower 11 to operate a contact 12. This coding device is normally at rest, but is set into operation when relay D becomes energized, the circuit then being from terminal X, through front contact 7 of relay D, and the motor 9 to terminal Y. Relay D is provided with a circuit which includes backcontact 5 oftrack relay B, so that relay D is deenergiz ed or energized according as relay R is energlzed or deenergized.

When relay D becomes energized, the circuit referred to above for the primary 1 of transformer T is opened at the back point of 1930. serial rim-461,968.

contact 6, and a new circuit forprimary lbecomes closed, this circuit being fromterminal X, through the front point of contact 6 of relay D, contact 12 of'the coding device C, front point of contact 8 of track'relay R for the section next in advance, and primary .4 of transformer T toterminal Y. When this moving. toward the right enters section AB,

.it will. deenergize track relay R, and this 7 in 1 turn will cause relay D' to become energized. Relay D will then set the coding device G into operation and will also interrupt the normal circuit for primary 4; of transformer T and will close the auxiliary circuit for thisprimary through contact 12. When the train leaves section A'B, track relay R being opened, uninterrupted alternating current will be supplied to transformer T to again pick up relay R, with the result that 0 relay D will become deenergized and the parts of the apparatus will then be restored to their normal positions.

If a shunt be placed across the rails of section AB, and is removed while relay R is 55 energized, it becomes necessary for track relay R to pick up on the coded current, but in some instances the periodic interruptions of the alternating current supplied to transformer T may be too rapid to effectively energize relay B. This is particularly likely to occur in the case of what is known as the cycle per minute code of the present-day standard code train control system. In order to insure that the track relay R will pick up under this 5 condition, I provide the cam 10 with one tooth 13 which is considerably longer than the normal teeth 13, so that once during each revolution of the cam, contact 12 will be held closed for more than the normal length of time. The i-c0 length of the tooth 13 may be such as to insure that relay Rwill pick up during the time that contact 12 is held closed by this tooth. I have found that one tooth of abnormal length in the cam 10 will not interfere with the normal operation of the train-carried apparatus used in the standard code train control system.

Although Ihave hereinshown and de-I scribed only one form of apparatus embody ing my invention, it is understood that various changes and modifications may be made therein within the scope of the appended claim without departing fromthe spirit and scope of my invention.

.Having thus described my invention, what I claim is: i

In combination, a section of railway track, a trackcircuit for said section including a source of alternating current and a track relay; a coder comprising a motor, a cam driven by said motor, and a contact operated by said cam for periodically interrupting the supply of current from said source to the track rails; and means for setting said coder into operation when said track relay becomes deenergized, said cam having a special tooth which is longer than the others whereby once during each revolution of the cam current will be supplied to the track rails for a longer period of time than normal, so that if the length of each normal tooth is insufficient to pick up the trackrelay when a shunt is removed from the rails the relay will pick up when said contact is operated by the special tooth.

In testimony whereof I afiix my signature.

GEORGE W BAUGHMAN. 

